Well, I'm not though, am I? I'm talking about the economy as well. And there is a much bigger difference between the parties than you're allowing.
A big part of the problem is that many people have no understanding of economics and/or a very short memory and/or just uncritically believe whatever the very partisan media they consume tell them. (This is by no means a problem that's unique to the US, obviously.)
In particular, they don't understand that there's often a delay of a year or two between a government doing (or failing to do) something and the effect being felt by the public. So it's an article of faith among GOP voters that Biden caused gas prices to rise a few years ago, because he was president at the time, and the president is in charge; so it must have been his fault, right? Except Trump caused it by blackmailing the Saudis into lowering their oil output precisely to drive up the international price of crude in order to benefit American producers.
Likewise, inflation shot up in 2022 mainly as a result of the economic disruption caused by the pandemic, which was as severe as it was because Trump bungled the response from the start, and in fact had disbanded the pandemic response unit that should have helped prepare the country for just such an eventuality. It's now back down almost to pre-pandemic levels at a virtually negligible 2.4%, thanks to Biden's policies, but many people have said they were going to vote Trump "to rein in inflation", which they still think is high because Fox News tells them it's high. No doubt once Trump is reinstalled in the White House, the narrative will suddenly switch to "Trump defeats inflation."
So Biden gets blamed for problems Trump caused the first time round, and Trump will take the credit for Biden's achievements. Meanwhile a "curse on both their houses" attitude among progressives who, like Trump supporters, are unaware of all this, can only ever benefit Trump.